High Velocity Gun Launch Fragment Impact Studies and How Events Can Go Very Wrong

Abstract

High velocity fragment impact studies have become an important factor in the testing of insensitive munitions (IM) to ensure compliance and to demonstrate the safe use of munitions, in an operational requirement. A 40mm calibre, high velocity long gun system has been developed by QinetiQ, to meet the NATO STANAG 4496 standard high velocity fragment impact test requirement. However, it uses an internal ballistic (IB) solution which is optimised for the higher velocity as defined in the STANAG document. A 30mm calibre gun system is used to meet the lower velocity fragment impact test requirement. Whilst the fragment’s impact velocity when using the 30mm gun system can be pushed to achieve impact velocities of ~2000m/s, there is a distinct gap in the ability to achieve terminal velocities between 2000m/s and 2530m/s using these two gun systems. To understand a munition’s reaction phenomena by fragment impact between these two figures would be a very desirable option and would be beneficial to the munition designer from the IM perspective. This paper will report and discuss some of the experimental results and the problems encountered during high velocity fragment impact studies with powder gun systems.